time-sharing (leisure)

The joint ownership of holiday accommodation by a consortium. Depending upon the number of shares acquired, each share holder is entitled to a specific period of use. A register of time-share owners exists, enabling them to exchange their accommodation for another during their holiday entitlement period.

But because computers in interactive use often spend much of their time idly waiting for user input, it was suggested that multiple users could share a machine by using one user's idle time to service other users. The first project to implement a time-sharing system was initiated by John McCarthy in late 1957, on a modified IBM 704, and later an additionally modified IBM 7090 computer. Although he left to work on Project MAC and other projects, one of the results of the project, known as the Compatible Time Sharing System or CTSS, was demonstrated in November, 1961. The first commercially successful time-sharing system was the Dartmouth Time-Sharing System (DTSS) which was first implemented at Dartmouth College in 1964 and subsequently formed the basis of General Electric's computer bureau services. DTSS influenced the design of other early timesharing systems developed by Hewlett Packard, Control Data Corporation, UNIVAC and others (in addition to introducing the BASIC programming language).

Other historical timesharing systems, some of them still in widespread use, include:

IBM CMS (part of VM/CMS) IBM TSS/360 (never finished; see OS/360) IBM Time Sharing Option (TSO) KRONOS (and later NOS) on the CDC 6000 series Michigan Terminal System Multics MUSIC/SP WYLBUR RSTS/E RSX-11 TENEX TOPS-10 TOPS-20 UNIX